Validation Server Control

Validation Controls and JavaScript

By default, the validation controls perform validation on both the client (the browser) and the server. The validation controls use client-side JavaScript and you get immediate feedback whenever you enter an invalid value into a form field. You can use the validation controls with browsers that do not support JavaScript (or do not have JavaScript enabled).

The page developer was responsible for creating the client-side and server-side logic for each and every validation check. Client-side JavaScript is supported on any uplevel browser. Supported browsers include Internet Explorer, Firefox, and Opera. This is a change from the previous version of ASP.NET, which supported only Internet Explorer as an uplevel browser.

You can use the validation controls with browsers that do not support JavaScript (or do not have JavaScript enabled). If a browser does not support JavaScript, the form must be posted back to the server before a validation error message is displayed.